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The plutonic body of Bostanabad-Meyaneh belt formed during the Cenozoic magmatism on the weast Alborz-Azarbaijan zone. The Oligocene plutonic rocks consist of alkaligranite, granodiorite and biotitegranite, intruded into the Eocene volcanic-sedimentary rocks. The predominant textures are granular, graphic and perthite. Geochemical evidence reveals that they are cogenetic and have features typical of calk-alkaline to high-K calk-alkaline, metaluminous with I-type nature. Enrichment in LILE (i.e. Cs, K, Rb and Th) rather than HFSE (Eg., Nb, Zr and Ti), typical negative anomalies of Nb and Ti and LREE enrichment in comparison to HREE, are important characteristics indicating that these rocks were formed in a magmatic belt in a subduction zone. Positive anomalies of Pb and K demonstrate the involvement of continental crust in evolution of parental magma. During magma ascent, assimilation processes, fractional crystallization and crustal contamination (AFC) took place simultaneously. Tectonic discrimination diagrams show formation of these rocks in VAG, Syn-COLG event and an mature continental arc setting with less than 45 Km crustal thickness. Primitive magmas should have formed by low degree melting of an enriched mantle wedge peridotite.

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Tarazoj-Soushab tectonic window is located between Tarazoj and Soushab villages at the upper corner of the northeast of 1:100,000 Hashjin sheet. This area is a part of the West Alborz Tertiary magmatic belt. Mafic igneous rocks include basaltic pillow lava and gabbro bodies and felsic igneous rocks include granite and trachytic flows. The main minerals of the gabbroic and basaltic rocks are plagioclase, olivine and clinopyroxene and the main minerals of the granitic rocks include plagioclase, orthoclase and quartz, and the trachyte consists mainly of potassium feldspar. Gabbroic and basaltic rocks show calc-alkaline nature and granitic and trachytic rocks have shoshonitic nature. Examination of chondrite and primitive-mantle normalized spider diagrams in basalts and gabbros indicates enrichment of LREEs relative to HREEs. The LILE and LREE enrichment and HREE depletion in the pattern may indicate low melting rate, high fugacity of CO₂/H₂O in the magma formation environment or high depth of generation of basaltic and gabbroic magma. Examination of chondrite and ORG-normalized spider diagrams in granites and trachytes indicate enrichment of light rare earth elements (LREE) and incompatible elements relative to heavy rare earth elements (HREE). These patterns show a marked depletion of Eu (especially in granites). Gabbroic and basaltic rocks are located in an oceanic environment with E-MORB basalts tendency and the granites and trachites associated with this assemblage belong to anorogenic granitoids (A-type) and subgroup A₁. These features indicate that the studied outcrops in the Tarazoj-Soushab tectonic window belong to the rift-related magmatism and opening of the Paleo-Tethys ocean (Paleo-Tethys II) in the northwest of Iran.

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The study area is located in the south of Qushadagh mountain range, in the north of Asbkhan village, Heris township. In terms of structural geology of Iran, this area is located in the main zone of Central Iran and Alborz-Azerbaijan sub-zone. The geological units of the region are including Eocene igneous and pyroclastic rocks with combination of andesitic, trachyandesitic, basaltic, tuffic and ignembritic. The semi-deep intrusive mass with Oligocene age, with the combination of quartz diorite, diorite and quartz monzonite in the form of stock and dyke is exposed in the area. Under the influence of hydrothermal processes originating from this intrusive mass and infiltration of fluids through the sedimentary-volcanic units of the Middle Eocene, extensive alterations (sericitic, medium argillic, propylitic and siliceous) have been taken place in the region. Preliminary results of geochemical studies of stream in the region led to the identification of several areas with grade 1, 2 and 3 anomalies of heavy minerals. The most important heavy minerals identified, include hematite, goethite, magnetite, pyrite-oxide, pyrite and zircon, These minerals and have closely relation to the alteration zones and veins mineralization. The conformity of the geochemical halos map with the geostructure and alteration map of the region shows a very high correlation between these regions and possibly the important role of faults and joints in the occurrence of alteration zones and abnormal regions. Anomaly maps and geostatistical analyzes performed on the findings in stream sediments and heavy minerals show that the enrichment of Ag, Au, Mo, Cu, As, Pb, Sb and Zn elements is higher than the background and the Au, Ag, Cu, As and Pb elements can be used as trace elements for epithermal gold reserves.
 

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The study area is located near the Zeinabad village, NW Tabriz. Precambrian to Cretaceous sedimentary units form the dominant outcropping rocks in this area. The investigated basic rocks including lava and diabasic dikes are intruded within the Late Triassic-Early Jurassic sandstone, conglomerate and shales of the Shemshak Formation. The basic rocks are extremely alterated and have abundant vesicles filled by secondary minerals of chlorite, calcite, Zeolite and opaque phases. Petrographic studies of the basic rocks reveal that the plagioclase forms the main constituent mineral and Fe-Mg bearing minerals (most probably hornblende) are completely altered to the calcite, chlorite, epidote and opaqe phases. The most significant textures are porphyry, glomeroporphyry, amygdaloid, sieve and sub-ophitic. Geochemically, the basic rocks are basalts with alkaline signitures. On the basis of variation diagrams, the compositions of analysed rocks are rich of U, Th and LILE (such as Ba, Rb). Positive anaomaly of Pb in these diagrams can be interpreted by the continental crust distribution and/or mantle wedge metasomatism related to the released fluids from subducted oceanic crust. Considering the REE diagrams, the rocks are rich in the LREE but poor in the HREE. High La can be related to Yb contents and can be interpreted to reveal their formations from the garnet bearing mantle sources. Tectonic setting of Zinabad basic rocks is determined as within plate setting. They form in relation with the extensional phases after continental collision during Cimmerian Orogeny in the Azarbaijan continental crust, NW Iran.
 

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The Jizvan region with an area of ​​45 km² is located about 70 km northwest of Zanjan town in the Tarom-Hashtjin metallogenic zone. The major rock units in the Jizvan area consist of a regular sequence of thin-layered tuff and breccia tuff with intermediate to basic compositions, interlayered with andesites and basalts. In addition, volcanic trachytic and porphyry andesitic rock units are also scattered in the region. Parts of the tuff and breccia tuff sequence are intruded by hypabyssal quartz monzonite, monzodiorite and syenite intrusions in the east of the region. As a result of this event, due to the presence of linear structures and the invasion of hydrothermal fluids, the above-mentioned rocks are affected by advanced argillic alteration. Carbonatic (malachite) and sulfidic (chalcopyrite, bornite, tetrahedrite-tennantite and chalcocite-covellite) copper mineralizations, along with pyrite, galena, sphalerite, arsenopyrite, quartz, calcite and goethite minerals are developed with a vein-veinlet texture in the above-mentioned units. Using the study of primary biphase fluid inclusions containing liquid and gas phases, homogenization temperatures from 95.6 °C to 268.9 °C with the highest frequency at 185 °C are recorded. The salinity of mineralizing fluids is between 4.65 and 23.8 wt% NaCl equivalent, while their density falls in the range from 0.77 to 1.08 g/cm³. Based on the fluid inclusion data, the mixing between magmatic and meteoric waters is the main cause for precipitation of metallic elements and the occurrence of mineralization in Jizvan area. These data overlap with the representative data of epithermal deposits.

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Chlorite group minerals have a wide range of chemical composition that reflect their physical and chemical conditions of crystallization. In this research, the chlorite mineral geothermometry method has been used to determine the alteration temperature of delay dykes in Sungun copper-molybdenum porphyritic deposit, located in the northwest Iran. Based on the microprobe data, the compositional changes of chlorite reflect a large differences in the content of silicon, aluminum, iron and magnesium elements in these dykes. The chemical composition of the chlorites in quartz diorite porphyry (DK1a, DK1b), diorite porphyry (DK3) and microdioritic (MDI) dykes placed in picnochlorite range of type clinochlor and quartz- dioritic dykes (DK1c) are in the penin range type of chamosite. Chlorite in quartz diorite porphyry (DK1a, DK1b, and DK1c) and diorite porphyry (DK3) dykes enrichment in the Mg-chlorite and microdioritic (MDI) dykes enrichment in the Fe-chlorite and are classified as trioctahedral chlorites. According to different geothermometric methods, chlorite minerals in quartz diorite porphyry (DK1a, DK1b, and DK1c), diorite porphyry (DK3) and microdioritic (MDI) dykes, have formed at temperatures of 237^°C, 217^°C, 115^°C, 276^°C and 247 ^°C respectively. These temperatures show the effect of hydrothermal fluids in the formation of chlorite and show that the chlorites of the studied area can be related to the effect of hot fluids originating from magma. The relationships between the SiO2 content and the crystallization temperature in Sungun late dykes show an inverse and strong correlation; so that high temperature chlorites in these dykes have lower Si content than chlorites crystallized at low temperatures. Therefore, the silica chlorite content of these dykes can be an indicator of their crystallization temperature. Chlorites have specific compositional changes and atomic substitutions that reflect their crystallization temperature.

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The studied area is located in the northwest of Iran within the western Alborz- Azerbaijan zone. The host rocks of the studied xenoliths are basaltic andesite and andesite. Xenoliths in volcanic rocks include gabbroic and diorite xenoliths. The main minerals of xenoliths include plagioclase, amphibole and clinopyroxene with minor minerals including biotite, orthopyroxene and opaque minerals. The main texture of xenoliths is granular and microlithic porphyric. Based on mineral chemistry, the composition of plagioclase, amphibole, pyroxene and biotite is oligoclase to andesine, chermakite to hornblende, augite and stonite respectively. Based on AlIV value (less than 1.5), amphiboles of xenoliths are placed in the active subduction-related continental margin. The thermo-barometric measurement of xenoliths, using the amount of total aluminum cations, indicates a pressure of 5.8 ± 0.6 kbar and a temperature of about 802°C in the crystallization environment. The studied clinopyroxenes with sub-alkaline composition show good compatibility with magmatic arc tectonic environment. Also, clinopyroxenes are formed in low to medium pressures, which indicates their crystallization during magma ascent at different depths. The amount of ferric iron in clinopyroxenes indicates the high fugacity of oxygen magma. The clinopyroxenes of diorite-gabbroic xenoliths were formed at a pressure of 12 kilobars and a temperature of about 1050°C.

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 The studied area is located in the northwest of Iran, East Azarbaijan province, and at a distance of about 30 km from the north of Sarab city. This area is part of the structural zone of Alborz. Based on petrographic and field studies, the lithology of the area includes an intrusive mass of quartz monzonite porphyry, the mass of granodiorite porphyry, dykes branching from the mass of granodiorite porphyry, and basalts. The main mineralogy includes plagioclase, quartz, potassium feldspar, clinopyroxene, biotite, and amphibole, alteration minerals in the studied rocks include sericite, chlorite, kaolinite, and iron oxides and often have porphyric, glomeroporphyric and Poikilitic texture. The most important variations include phyllic, argillic, and propylitic zones. Sulfide minerals observed in the area are mostly pyrite, chalcopyrite, sphalerite, and molybdenite, which have been converted into iron oxides and hydroxides (hematite) at some points. The mineralized texture is mainly scattered grains and veins. Examining the changes of rare earth elements and rare elements of porphyry masses shows positive anomalies of elements Li, Pb, Th, and U and negative anomalies of elements P, Zr, Ti, and Nb. A specific enrichment of LREE/HREE elements can be seen. The ratio of Eu/Eu* in altered samples is lower than that of healthy samples, and the ratio of Ce/Ce* is almost the same for healthy samples and most of the altered samples. In addition, the subtraction factors of (La/Yb)N, (La/Sm)N, and (Gd/Yb)N in altered samples are higher than in healthy samples. Light rare earth elements show an increasing trend and heavy rare earth elements have increased and decreased during the region's transformation process. The enrichment of U and Th elements is probably due to the prevailing acidic conditions and surface absorption by clay minerals and also due to the presence of zircon in the mineral network. Elements with high field strength show enrichment in most of the altered samples compared to the source rock, and only the Hf element shows depletion.

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Molybdenum-copper deposit of Shele Boran is located about 2 km northeast of Ahar within the Ahar-Arasbaran metallogenic belt. This deposit is hosted by Eocene volcanic igneous rocks (tuff, agglomerate, andesite and dacite) and Oligocene intrusive igneous bodies (granite, granodiorite and diorite). These rocks host hypogene potassic, phyllic, propylitic, and argillic alteration zones where mineralization is often associated with the potassic and phyllic alteration zones. In these rocks, hypogene mineralization is predominant and occured mostly in the form of dissemination and vein-veinlet (chalcopyrite, molybdenite, pyrite and magnetite). This mineralization is covered by supergene accumulations such as hematite, goethite, malachite and azurite in the surface part of deposit. Four types of fluid inclusion in quartz crystals associated with mineralization were identified, including (1) two-phase fluid inclusion liquid-rich (L-V), (2) two phase fluid inclusion gas-rich (V-L), (3) three-phase liquid-gas-solid (L-V-S) and (4) vapor-rich monophase (V). The studied fluid inclusions have a homogenization temperature ranging from 123-447°C. The L-V-S three-phase fluid intermediates are homogenized by the disappearance of the NaCl crystal in the temperature of 156-317°C, corresponding to the salinities in the range of 30-40% by weight of NaCl. Two phase inclusions liquid-rich (L-V) intermediates show salinities in the range of 0.36-15.9% by weight equivalent of NaCl. Based on microthermometry data, boiling, mixing and simple cooling of mineralizing fluids are effective mechanisms in the formation and expansion of this deposit. The ores were most likely of magmatic and magmatic-meteoric origin. Alteration and mineralization of mineral accumulations, and microthermometric data confirm the classification of the Shele Boran deposit as a porphyry molybdenum-copper deposit.   

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Contact metamorphism of Mishu is about 1 km wide and  is surrounded the  Cadomian Mishu granites. This Contact metamorphism is located in the southwest of Marnd city, Azerbaijan Province northwest of Iran. Based on injection of granites into Kahar Formation, the contact metamorphism facies can be identified easily, respectively albite-epidote hornfels to pyroxene hornfels facies. At high grade, hornfels with appropriate component show evidence of partial melting.  Contact rocks of Mishu that are exposed in south west of Eyshabad village spans a wide range in grade and proceeding upgrade metamorphic's phase that occurs such as: 1) slates which were regionally metamorphosed relate to Kahar Formation, 2) biotite cordierite hornfels that first appear by occuring biotite and cordierite in the spot slate, 3) andalusite cordierite  biotite hornfels with abundant porphyroblasts of cordierite and andalusite and 4) developments of K-feldspar-sillimanite hornfels and rocks with appearance of anatectic migmatites. This paper focus on contact rocks  from the view point of mineralogy, texture, chemical composition and tectonic setting of protolith are distinguish.

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The Zarshloo manganese deposit is situated approximately 40 kilometers southwest of Mianeh city, in the northwestern part of Azerbaijan province, Iran. This region is tectonically located within the Alborz-Azerbaijan zone. The dominant lithology in the area consists of Oligocene-Miocene volcanic rocks, predominantly basaltic andesites and ignimbrites. These volcanic rocks exhibit a porphyritic to microlitic porphyritic texture, with phenocrysts of plagioclase, hornblende, pyroxene, and olivine. The principal ore minerals are pyrolusite and manganite, accompanied by minor barite, silica, and calcite. A variety of textures, including cauliflower, kidney, dendritic, concentric banding, and pisolitic growth, are observed in the deposit. The Zarshloo deposit is hosted within a fault-shear zone and is primarily confined to basaltic andesite. The main manganese orebody strikes north-south and extends for approximately 150 meters. The rocks in the area exhibit significant shearing. The ore mineral occurs as irregular veins with a nearly vertical dip, and is readily visible due to its hardness and resistance to weathering. Geochemical evidence suggests that the manganese mineralization is related to hydrothermal fluids, forming as massive and fracture-filling veins with kidney and cauliflower textures. The average grade of manganese in the Zarshloo ore is 48%.